Creation of defects in nanograin tungsten

Grain boundaries play an important role in nanocrystalline material properties. The present molecular dynamics study is focused to the role of the grain boundaries in radiation damage. Computer simulations of cumulative self-atom irradiation were conducted for 4 different types of grain boundary configurations (Σ3<110>{112}, Σ3<110>{111}, Σ5<100>{130}, Σ5<100>{120}), at impact energy of 1 keV, and for two temepratures, 300 K ad 1000 K. Five different interatomic potentials for tungsten were applied to determine the most suitable one for our simulation conditions. The size of the target tungsten structure was 160,000 atoms. The calcuations were performed at supercomputing facilities of NCCS (Titan, EOS) and of XSEDE (Stampede 2 and Comet). The analysis of the surface morphology, number and structure of deffects, sputtering and implantation revealed the mechanism of the direct and indirect mutual interactions of the collision cascades and grain boundaries.